3. Document Object Model Views

3.1. Introduction

A document may have one or more "views" associated with it, e.g., a computed view on a document after applying a CSS stylesheet, or multiple presentations (e.g., HTML Frame) of the same document in a client. That is, a view is some alternate representation of, or a presentation of, and associated with, a source document.

A view may be static, reflecting the state of the document when the view was created, or dynamic, reflecting changes in the target document as they occur, subsequent to the view being created. This Level of the DOM specification makes no statement about these behaviors.

This section defines an AbstractView interface which provides a base interface from which all such views shall derive. It defines an attribute which references the target document of the AbstractView. The only semantics of the AbstractView defined here create an association between a view and its target document.

There are no subinterfaces of AbstractView defined in the DOM Level 2.

However, AbstractView is defined in and used in this Level in two places:

• A Document may implement a DocumentView that has a default view attribute associated with it. This default view is typically dependent on the implementation (e.g., the browser frame rendering the document). The default view can be used in order to identify and/or associate a view with its target document (by testing object equality on the AbstractView or obtaining the DocumentView attribute).
• A UIEvent typically occurs upon a view of a Document (e.g., a mouse click on a browser frame rendering a particular Document instance). A UIEvent has an AbstractView associated with it which identifies both the particular (implementation-dependent) view in which the event occurs, and the target document the UIEvent is related to.

The interfaces found within this section are not mandatory. A DOM application can use the hasFeature method of the DOMImplementation interface to determine whether they are supported or not. The feature string for all the interfaces listed in this section is "Views".

3.2. Interfaces

Interface AbstractView (introduced in DOM Level 2)

A base interface that all views shall derive from.

IDL Definition

// Introduced in DOM Level 2:
interface AbstractView {
  readonly attribute DocumentView     document;
};

Attributes

document of type DocumentView, readonly

The source DocumentView of which this is an AbstractView.

Interface DocumentView (introduced in DOM Level 2)

The DocumentView interface is implemented by Document objects in DOM implementations supporting DOM Views. It provides an attribute to retrieve the default view of a document.

IDL Definition

// Introduced in DOM Level 2:
interface DocumentView {
  readonly attribute AbstractView     defaultView;
};

Attributes

defaultView of type AbstractView, readonly

The default AbstractView for this Document, or null if none available.